Rod Laver, the last man to win all four grand slam tournaments in a single season, believes Wimbledon and US Open champion Andy Murray is capable of replicating the feat.

The 74-year-old Australian - who notched up two calendar slams in his career, in 1962 and at the dawn of the Open era in 1969 - expects the Briton to lay claim to the world No. 1 ranking at some stage in his career after allying a ruthless streak to his world-class talent.

"I never doubted [Murray] had the ability to beat the world's best players - Roger Federer, Rafael Nadal, and Novak Djokovic - in big matches, but my one reservation about Murray was his lack of self belief and his failure to play enough 'kill' shots when he was on top," Laver told The Scotsman.

"I now believe Murray has proved he does have both the self-belief and the aggression needed to beat anybody. He's also shown that he knows how to handle the pressure on crucial points because he's a smarter player than before.

"The difference with Murray is that now he's got two majors to his name, including the big one - Wimbledon - so that should give him the confidence to go on and win more grand slam tournaments. I would be very surprised if he didn't."

No player has won all four grand slams in a calendar year since Steffi Graf in 1988, while Serena Williams is the last player to have held all four slams at the same time after consecutive major wins in 2002 and 2003, but Laver believes Murray could follow in their footsteps.

"I think we need to wait to see if Andy wins a few more majors first, but if he does that then it's possible he could win a calendar grand slam," Laver added."The most difficult of the four majors for him to win is probably the French Open, but he's got the game to win on clay as he proved by reaching the semi-final in 2011.

"Rafael Nadal has been virtually unbeatable in the French Open as his record of eight wins in nine years suggests, but equally his knees must be a big concern. I don't believe they will hold up forever, so who knows what Andy could achieve if he keeps playing like he did at Wimbledon.

"One of the big positives about Murray is his fitness," Laver continued. "If he can stay fit, then I would expect him to take over as world No. 1 in the foreseeable future, but it won't be easy."